a. Field of Invention
The invention relates to a device for controlling the position of a hydraulic feed drive, for a press or punch press, through a device controlling the flow of the hydraulic liquid to a cylinder/piston arrangement.
Description of the Prior Art
In commercially available hydraulic presses or punch presses, their position, i.e., the distance between the upper and the lower position is set through open loop control schemes utilizing mechanical or electronic cam control mechanisms which act on the cylinder/piston arrangement. Intervention is largely exercised manually by the operator. This results in relatively long setup and resetting times, and external disturbances such as temperature drifts are not compensated automatically.